Improvement in electric lights



T. A. EDISON. Electric- Light.

Patented Sept. 16, 1879.

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UNITED STATE$ PATENT OFFICE.

IMPROVEMENT IN ELECTRIC LIGHTS.

Specification forming part of Letters Patent No. 219,628,

dated September 16, 1879 application filed December 9, 1878.

To all whom it may concern:

Be it known that I, THOMAS ALVA EDIsoN, of Menlo Park, in the county of Middlesex and State of. New Jersey, have invented an Improvement in Electric Lights, and the following is declared to be a description of the same.

The object of this invention is to produce a candle or light-giving body by the incandescence of a conductor of electricity in the form of a cylinder, prism, or other mass of a size adapted to yield the required volume of light. 7 The invention consists in an electric-lightgiving body formed of a conductor, such as finelydivided platinum, iridium, ruthinium, or other metal difficult of fusion, incorporated with non-conducting material.

The candle, made as aforesaid, can be of any desired size or shape, and the metallic particles become incandescent by the passage of the current, and the non-metallic materials are luminous and increase the brilliancy. This is accomplished by a comparatively small electric current. I mix withsuch finely-divided conductors infusible materials-such as oxide of magnesium or zirconiumin different proany degrees of conductivity required.

In some instances I saturate rods, sheets, or other forms of infusible oxides witha salt of V and reduce the sameby. heat to a metallic state.

I will mention that the use of a non-conducting material is not absolutely necessary, as the finely-divided metals, owing to their porosity, have high resistance, and become easily incandescent; but I. preferto use the non-conductor. Q

In Figure 1 is shown a lamp composed of strength of the current finely-divided iridium mixed with oxide ofzerconium and molded in the form of a split hollow cylinder, Fig. 2 is a detached section of the same. Fig. 3 is aperspective view, and Fig. 4 is a plan view. 7

The cylinder being split, the current enters the binding-post A, passes through the lever L, through the regulating-wire a to the plate 9, thence up one side of the iridium cylinder or, down the other side to the plate h, thence, by wire k, to the regulating-screw m and binding-post n".

The regulation of the "temperature of the cylinder :10 is obtained by the thermal-current regulator in the same manner as is shown in my application N o. 156, filed October 14, 1878.

The incandescent conductor made in this manner may be of any desired shape.

I-claim as my i11vention- 1. For electric lighting, a conductor of electricity formed of finely-divided metal incorporated with a non-conductor of electricity, substantially asset forth.

2. A rigid electric-light-giving body having a longitudinal incision or separation from the base to near the end, for insuring the circulation of the electric current through the entire body, substantially as set forth.

3. In combination with a rigid light-giving body having a longitudinal incision, an expansive thermal-circuit regulator to control the substantially as set forth.

Signed by me this 3d day of December, A.

THOMAS A. EDISON. Witnesses:

STOCKTON L. GRIFFIN, GEO. E. GARMAN.

by the heat developed, 

